The invention is directed to improvements in a method and apparatus for the separation of materials into a thin or light phase and a thick or heavy phase, and more particularly to an arrangement for effecting and facilitating the discharge of the thick phase and mixing the thick phase with a fluidizing gas before it leaves the drum.
In previous methods of separation with a solid bowl worm centrifuge, the thick or heavy phase material is separated from the liquid or light phase in the operation and both phases are discharged from the drum through separate outlets. In the separation of certain materials such as those which are permeated with a solvent containing material, the solvent material may have the characteristic of being noxious and reeking, requiring that it be subjected to an appropriate after-treatment in a special unit as the heavy phase leaves the separator. This is necessary so that the heavy phase can be satisfactorily handled and subsequently safely stored or further processed.
Further, the discharge of thick material from a solid bowl worm centrifuge frequently presents difficulties particularly when the thick material has a relatively low viscosity. What occurs is that it is not appropriately seized by the worm conveyor helix in the conical jacket part of the centrifuge drum and therefore is not discharged to the outside but instead flows back between the worm helix and the inside wall of the conical drum into the separating space. In this space, the phases are already separated from one another and are again remixed so that the separating action of the separator is adversely affected.
An object of the invention is to provide an improved solid bowl separator and particularly one which can more satisfactorily handle heavy phase material of low viscosity or of varying viscosities.
A further object of the invention is to provide a solid bowl worm separator wherein the heavy phase material can be treated with a fluidizing gas while within the solid bowl separator so that admixing between the substance and heavy phase occurs within the separator and the material flowing form the separator is of a more appropriate nature for further handling and treatment.
A still further object of the invention is to provide an improved method and apparatus whereby particularly undesirable heavy phase fractions of material which are discharged form the separator are first treated by being admixed with gas within the separator at a location where the heavy fraction no longer has the opportunity to mix with the lighter fraction.
A still further object of the invention is to provide an improved method and apparatus involving use of a solid bowl worm separator wherein the separated heavy phase is admixed with a fluidizing gas before leaving in such a manner that the separating function of the separator is not adversely affected by undesirable heavy phase materials and whereby the heavy phase material is discharged in such a condition that it continues to flow freely and easily from the separator.